Swift Performance provides Youtube Smart Embed feature to prevent embeded Youtube videos harm performance.
If you enable this feature, Swift Performance will change Youtube embeds to a static picture placeholder, when you click to it, it will start the video. This feature is not working for videos where autoplay is enabled.
Exclude Youtube Videos
You can exclude specific videos if it is necessary. You can use the full- or partial URL to exclude videos.
On mobile placeholder will be replaced to the original video embed before it appears in the viewport. By default it happens when the video is 50px before the viewport, however you can change this to any value.